San Antonio, TX—In determining the optimal treatment of ductal carcinoma in situ (DCIS), gene expression profiling using the Oncotype DX DCIS Score is more cost-effective than standard clinical assessment, primarily because it avoids radiotherapy for approximately 66% of these patients.

That is the conclusion from an independent (non–industry-funded) study presented at the 2012 CTRC-AACR San Antonio Breast Cancer Symposium by Michael D. Alvarado, MD, Associate Professor, Department of Surgery, University of California School of Medicine, San Francisco.

“The Oncotype DX assay as a strategy for identifying women who can forego radiation after lumpectomy for DCIS is cost-effective when you place it into the population that was used for the validation study,” Dr Alvarado told Value-Based Cancer Care.

Currently, more than 70% of women who receive a lumpectomy for DCIS undergo whole-breast radiation, he said.

Oncotype DX–based DCIS Score is a recently validated molecular assay for DCIS that identifies low-risk biology. The investigators sought to determine the cost-effectiveness of using the DCIS Score in risk stratification of newly diagnosed DCIS. They designed a Markov model that compared the use of the molecular assay to clinical assessment in determining the need for radiation in the validated cohort. Relevant outcomes were simulated over a lifetime horizon for a 55-year-old woman.

The investigators estimated the rates of locoregional recurrence and metastatic disease, and they input the following costs:

Oncotype DX test: $4000

5 weeks of radiotherapy: $8093

Radiotherapy indirect costs: $1467

Lumpectomy procedure: $2446

Mastectomy plus reconstruction: $9411.

They assumed a 50% reduction in local recurrences with radiotherapy.

“On average, the intervention strategy costs less than the standard strategy by about $1000 per patient, with similar life expectancies and quality-adjusted life-years,” Dr Alvarado reported.

“Because the intervention strategy (the molecular assay) was less costly, we calculated the ICER [incremental cost-effectiveness ratio] for changing from the intervention strategy to the standard strategy.

The ICER for changing the strategy was about $95,000 per QALY [quality-adjusted life-year], and this falls at the upper limit of the societal willingness-to-pay threshold of $100,000,” he said. “However, the difference in QALYs between strategies is minimal—only 4.38 days separated them. The real difference is in costs.”

The cost-effectiveness of the assay would not be seen should its upfront cost exceed $5138, Dr Alvarado reiterated. But at a cost of $4000, cost-effectiveness was demonstrated.

“Although the standard strategy falls just within the societal willingness-to-pay threshold, it is less costly to do the assay, and it spares about 66% of patients radiation therapy,” he concluded.

Dr Alvarado emphasized that the cost-effectiveness was driven by the fact that approximately 66% of patients would avoid radiation. “That’s where the cost-savings are,” he said, adding that their model does not take into account the negative impact of overtreatment on utility values; therefore, the difference is probably an under­estimate.